M. Narasimhulu

Isolation, characterization and biological evaluation of bioactive metabolites from Nocardia levis MK-VL_113.

An Actinomycete isolate found to be prominent in the laterite soils of Acharya Nagarjuna University (ANU) Campus, Guntur was identified as Nocardia levis MK-VL_113 by 16S rRNA analysis. Cultural, morphological and physiological characteristics of the strain were recorded. Screening of secondary metabolites obtained from 4-day old culture broth of the strain led to the isolation of two fractions active against a wide variety of Gram-positive, Gram-negative bacteria and fungi. The structure of the first active fraction was elucidated using FT-IR, EI-MS, (1)H NMR and (13)C NMR spectra and identified as 1-phenylbut-3-ene-2-ol which is first time reported as a natural product. The compound exhibited good antimicrobial potential against the opportunistic and pathogenic bacteria and fungi. The antifungal activity of the strain and its metabolite were further confirmed with in vitro and in vivo studies. Evidence for the antagonism of the strain against Fusarium oxysporum, causing wilt disease in sorghum was demonstrated by the formation of inhibition zone in in vitro plate assay and reduction in the incidence of wilt of sorghum plants by using a green house trial. Analysis of the rhizosphere soil extracts by high performance liquid chromatography also demonstrated the production of the compound by the strain under in vivo conditions. As compared to the commercial fungicide mancozeb, the bioactive compound, 1-phenylbut-3-ene-2-ol was highly effective in controlling wilt of sorghum. Besides, the partially purified second fraction (PPF) subjected to gas chromatography-mass spectrometry revealed the presence of phenylethyl alcohol, dibutyl phthalate and 1,2-benzenedicarboxylic acid, 3-nitro.

Synthesis of yashabushidiol and its analogues and their cytotoxic activity against cancer cell lines.

A total synthesis of yashabushidiol (1a), a linear diarylheptanoid having 1,3- diol system and its analogues has been achieved by alkynylation of 3-hydroxy-5-phenyl pentanal with substituted phenyl acetylenes. All the compounds have shown significant anti-proliferative activity on human leukemia (THP-1, U-937) and melanoma (A-375) cell lines. Compounds 2a and 2b were found to be most potent with an IC(50) of 12.82 microg/mL and 12.62 microg/mL, respectively, on THP-1 leukemia cell line.

Simple and Selective Removal of the t‐Butyloxycarbonyl (Boc) Protecting Group on Indoles, Pyrroles, Indazoles, and Carbolines

Abstract A highly selective and efficient deprotection of the N‐t‐butoxy carbonyl (N‐Boc) group on indoles, pyrroles, indazoles, and carbolines has been achieved in high yields using a catalytic amount of NaOMe as a base in dry MeOH, at ambient temperature. IICT Communication No. 060512.

Semi-synthesis and bio-evaluation of polybrominated diphenyl ethers from the sponge Dysidea herbacea

The sponge Dysidea herbacea was collected from the Mandapam Coast, Tamilnadu, India. Isolated gram quantities of hydroxylated polybrominated diphenyl ether (HO-PBDE) and semi-synthesized a series of new PBDEs derivatives and tested them for antibacterial and cytotoxic activities.